Arc extinguishing insulator



March 9, 1937. A. M. JACKSON ARC EXTINGUISHING INSULATOR Filed Feb. 8, 1952 @Zexaydew JQf S Patented Mar. 9, 1937 UNITED STATES PATENT OFFICE ARC EXTINGUISHING INSULATOR Application February 8 1932, Serial No. 591,688

3 Claims.

The invention relates to the support and insulation of high tension lines and has for its general object the provision of means to eliminate or reduce, in a simple, economical and practical 5 manner, interruptions to service caused by lightning on transmission lines.

The principal object of the invention is to provide a combined insulator and are extinguishing means embodied in or formed as a single unit.

An important object is to provide an insulator of hollow form and embodying electrodes contained therein defining a spark gap to permit lightning discharge and to disrupt by explosive action resulting from the rapid formation of gases in a small space the sixty cycle dynamic are which tends to follow the ionized path of the lightning discharge.

Another object of the invention is to provide a device which combines all of the features of an electric transmission line insulator or string of insulators and an arc extinguishing device or lightning arrester without it being necessary to provide adjunctive or extraneous auxiliary extinguishing means, the device being moreover capable of useto replace the different well known types of insulators used in standard equipment.

Another object of the invention is to provide a device of this character which may be manufactured, handled, sold and installed as a complete and distinct entity and placed in service in the same manner and with the same ease as an insulator of ordinary pattern.

A more specific object is to provide an insulator of this character of hollow or tubular formation equipped with metallic fittings at its ends and usable as a suspension insulator, the fittings having openings permitting discharge of the gases formed as the result of an electrical discharge between the caps which are formed as electrodes.

An additional object is to provide an insulator of this variety which in addition to possessing the above pointed out characteristics will be sim ple and inexpensive to make as well as easy to install, positive in action, efiicient and durable in service, and a general improvement in the art.

To the attainment of the foregoing and other objects and advantages, the invention preferably consists in the details of construction and the arrangement and combination of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawing in which:

Figure l is a side elevation of an insulator constructed in accordance with the invention,

Figure 2 is a vertical or longitudinal section through the upper end, the view being taken at right angles to Figure 1, and

Figure 3 is a horizontal cross sectional view taken on the line 3-3 of Figure 1.

Referring more particularly to the drawing I have shown the device as comprising, broadly, an elongated cylindrical hollow or tubular body ID of porcelain, glass or other suitable insulating material provided at its ends with metal fittings indicated as a whole by the numeral ll. Each of these fittings is represented as comprising a single metallic member conveniently formed as a casting and comprising a body E2 of cap-like form constructed somewhat in the nature of a spider and provided with suspension means l3 whereby the device may be suspended from a support and connected mechanically with a clamp or the like for holding a conductor. The outer end of each fitting is closed while the inner end is of ring-like formation as shown at I4 so as to engage about an end of the tube It] to which it is secured as by cement or its equivalent It. The outer surface of the tubular member may be roughened, sanded or otherwise treated within the confines of the ring-like portion I4 of the fittings for the purpose of providing an adequate grip for the cement and the inner periphery of the ring-like metallic portion may also be roughened, corrugated or otherwise prepared for the same purpose. Naturally the remainder of the tubular member is intended to be glazed, certainly outside and preferably also inside, in the customary manner so as to prevent absorption of moisture. To prevent access of water to the ocment l5 there is preferably a coating or band 56 of asphaltum or other bituminous or in fact still other waterproof material covering the joint between the tubular member and each fitting.

Up to this point the insulator will function in the same manner as any other. However, in order to obtain the combination of an insulator and self-contained arc extinguishing means, I provide a spark gap to take care of a lightning discharge which may occur along the line. To accomplish this I provide the terminal fittings H with electrodes which are of course spaced apart and which enter the ends of the tubular insulating body iii. In the present instance these electrodes, represented at H, are formed integrally with the cap-like fittings and project a short distance into the ends of the member l6. Moreover each of the fittings is provided with ODPO- site laterally disposed openings i3 extending to the outer sides of the fittings. In addition it is preferable that the electrodes ll be wedge shaped with their thinnest portions at the free ends, the sides merging into curved surfaces I 9 at one of the walls of the openings It for a purpose to be described.

From actual practice I have discovered that it may be preferable to provide the tubular insulating body l0 with a lining 2!! of fiber or the like. The reason for this liner is that after numerous flash-overs the porcelain tube has a tendency to become metal coated on the inside whereas a liner or fiber or some other equivalent material is free from this objection. However, it should be understood that the use of the liner is not essential especially as there is some probability that it might have to be replaced in time.

The device is used in thesame manner as conventional types of insulators and it is clear that the tubular member Ill may be made of any desired length, of course within manufacturing limits, depending upon the particular installation. As an insulator the device functions like any other but it will be noted that in the event of a lightning discharge flash-over will occur between the electrodes ii. The heat generated by such discharge causes expansion of the air within the tube and the discharge itself may generate gases and the air and such gases being expanded very rapidly will be expelled with explosive force through the openings it in the metal fittings, thereby disrupting the arc and preventing the formation of the sixty cycle dynamic discharge which generally or at least frequently follows the ionized path of the initial arc. Such being the case it is clear that the device emciently performs the function of an expulsion fuse which in the present instance has the great advantage of being a part of the insulator itself instead of some separate device attached to or used in combination with one or more insulators.

From the foregoing description and a study of the drawing, it is believed that the construction, operation and advantages will be readily apparent to one skilled in the art without further explanation.

While I have shown and described the preferred embodiment of the invention, it should be understood that the disclosure is merelyan exemplification of the principles involved as the right is reserved to make all such changes in the details of construction as will widen the field of utility and increase the adaptability of the device provided such changes constitute no de parture from the spirit of the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. A suspension insulator comprising an elongated tubular body, similar metallic fittings secured upon the ends thereof and provided with integral electrodes entering the ends of the body, said fittings having openings establishing communication between the interior of the body and the atmosphere, said openings in each fitting being located at opposite sides of the electrode and opening out at the sides of the fitting, the

electrodes being of wedge shape with their thinner ends innermost to prevent obstruction of flow of expanded gases within the body.

2. An insulator comprising an elongated tubular body, metallic fittings secured upon the ends thereof and provided with electrodes entering the ends of the body, said fittings having openings establishing communication between the interior of the body and the atmosphere, said openings in eachfitting being located at the opposite sides of the electrode and opening out at the sides of the fitting, the electrodes being of wedge shape with their thiner ends innermost and having their sides merging into the walls of the openings along curves so as to facilitate escape of gases expanding within the body in the event of a fiashover.

3. In an insulator, an elongated tubular body of dielectric material, a metallic cap secured exteriorly upon one end thereof, and an electrode carried by the cap and projecting into the bore of the tubular body beyond the line of the edge of the cap, said cap being formed with openings at opposite sides of the electrode, said electrode being of wedge shape and said openings having one wall flush with the end of the tubular body and having their opposite walls formed as continuations of the sides of the electrode.

ALEXANDER M. JACKSON. 

